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International audience; Background: Recent years have witnessed a considerable increase in clinical trials of new investigational agents for Fabry disease (FD). Several trials investigating different agents are currently in progress; however, lack of standardisation results in challenges to interpretation and comparison. To facilitate the standardisation of investigational programs, we have developed a common framework for future clinical trials in FD.Methods and findings: A broad consensus regarding clinical outcomes and ways to measure them was obtained via the Delphi methodology. 35 FD clinical experts from 4 continents, representing 3389 FD patients, participated in 3 rounds of Delphi procedure. The aim was to reach a consensus regarding clinical trial design, best treatment comparator, clinical outcomes, measurement of those clinical outcomes and inclusion and exclusion criteria. Consensus results of this initiative included: the selection of the adaptative clinical trial as the ideal study design and agalsidase beta as ideal comparator treatment due to its longstanding use in FD. Renal and cardiac outcomes, such as glomerular filtration rate, proteinuria and left ventricular mass index, were prioritised, whereas neurological outcomes including cerebrovascular and white matter lesions were dismissed as a primary or secondary outcome measure. Besides, there was a consensus regarding the importance of patient-related outcomes such as general quality of life, pain, and gastrointestinal symptoms. Also, unity about lysoGb3 and Gb3 tissue deposits as useful surrogate markers of the disease was obtained. The group recognised that cardiac T1 mapping still has potential but requires further development before its widespread introduction in clinical trials. Finally, patients with end-stage renal disease or renal transplant should be excluded unless a particular group for them is created inside the clinical trial.Conclusion: This consensus will help to shape the future of clinical trials in FD. We note that the FDA has, coincidentally, recently published draft guidelines on clinical trials in FD and welcome this contribution.

Newborn screening (NBS) prevents morbidity and mortality by screening babies for selected disorders in the first days of life so that early diagnosis and treatment can be initiated. Congenital disorders impact an estimated 8 million or 6% of annual births worldwide, and of the top five that contribute 25% to the global burden of these disorders, three can be identified and managed by NBS. There are determined pockets of activity in Latin America, Sub-Saharan Africa, and the Asia Pacific region, where partnerships among government, non-governmental organizations, academia, the private sector and civil society are developing novel NBS programs that are both saving lives and preventing disability in those who survive.

Mucopolysaccharidosis type I is a rare autosomal recessive disorder caused by deficiency of α-l-iduronidase (IDUA) which leads to a wide spectrum of clinical severity. Here, we describe the case of four male patients who present the previously undescribed p.L18P mutation. Patient 1 (p.L18P/p.L18P) presents, despite multiple joint contractures, an attenuated phenotype. Patient 2 (p.L18P/p.W402X) was diagnosed at 4 years of age with bone dysplasia, coarse facies, limited mobility, claw hands and underwent bilateral carpal tunnel surgery at 6 years of age. Patients 3 and 4 (both p.L18P/p.L18P) are brothers. Patient 3 was diagnosed at 4 years of age, when presented claw hands, lower limb and shoulder pain, restricted articular movement and bilateral carpal tunnel syndrome. Patient 4 was diagnosed at 17 months of age when presented lower limb pain at night, respiratory allergy and repeated upper airways infections. Bioinformatics analysis indicates that p.L18P mutation reduces the signal peptide to 25 amino acids and alters its secondary structure. In conclusion, we report a new IDUA variant that alters the structure of the signal peptide, which likely impairs transport to lysosomes. Moreover, it leads to a distinct attenuated phenotype with mainly bone and cartilage symptoms, without visceromegalies, heart disease, or cognitive impairment.

This 48-week, randomized, placebo-controlled phase 3 study (DMD114044; NCT01254019) evaluated efficacy and safety of subcutaneous drisapersen 6 mg/kg/week in 186 ambulant boys aged >=5 years, with Duchenne muscular dystrophy (DMD) resulting from an exon 51 skipping amenable mutation. Drisapersen was generally well tolerated, with injection-site reactions and renal events as most commonly reported adverse events. A nonsignificant treatment difference (P = 0.415) in the change from baseline in six-minute walk distance (6MWD; primary efficacy endpoint) of 10.3 meters in favor of drisapersen was observed at week 48. Key secondary efficacy endpoints (North Star Ambulatory Assessment, 4-stair climb ascent velocity, and 10-meter walk/run velocity) gave consistent findings. Lack of statistical significance was thought to be largely due to greater data variability and subgroup heterogeneity. The increased standard deviation alone, due to less stringent inclusion/exclusion criteria, reduced the statistical power from pre-specified 90% to actual 53%. Therefore, a post-hoc analysis was performed in 80 subjects with a baseline 6MWD 300-400 meters and ability to rise from floor. A statistically significant improvement in 6MWD of 35.4 meters (P = 0.039) in favor of drisapersen was observed in this subpopulation. Results suggest that drisapersen could have benefit in a less impaired population of DMD subjects.

Descriptive statistics on change from baseline to year 2 (MOR-001) or week 120 (MOR-005) by dosing cohort. (PDF 89 kb)

Descriptive statistics on change from baseline to year 2 (MorCAP) or week 120 (MOR-005). (PDF 74 kb)

Summary of adverse events. (PDF 64 kb)

Study design. After completion of MOR-004, patients initially randomized to 2.0 mg/kg/week (QW-QW cohort) or 2.0 mg/kg every other week (QOW-QOW cohort) remained on their assigned dosing regimen. Patients taking placebo were randomized to one of the two dosing regimens (PBO-QOW or PBO-QW cohort, respectively). After a review of efficacy and safety results from MOR-004 established the recommended dose for part 2, all patients were switched to 2.0 mg/kg QW. Specific week of transition ranged from week 36â 96, depending on enrollment timing. (PDF 866 kb)

LS mean change from baseline to year 2 (MorCAP) or week 120 (MOR-005) based on a repeated-measures ANCOVA modela. (PDF 84 kb)

Mucopolysaccharidosis IVA is a lysosomal storage disorder leading to an increase in glycosaminoglycans storage. Genistein is an isoflavone capable to inhibit glycosaminoglycans production. The objective of this study was to analyze the in vitro effect of different concentrations of genistein on DNA injury in mucopolysaccharidosis IVA patients. The lower concentration tested (10 μM) showed a significant increase on DNA injury in vitro, although higher concentrations (30 μM and 50 μM) showed higher DNA damage.

Background Lysosomal storage diseases (LSD) are a group of genetic conditions which could present a vast spectrum of abnormalities that may include skeletal abnormalities, organ dysfunction, neuronal involvement, and tissue accumulation of complex molecules, among other manifestations. Definitive diagnosis of LSD is generally obtained by specific enzyme assays performed in leukocytes, fibroblasts, or more recently, dried-blood filter paper (DBFP) samples. Methods We recently introduced dried-leukocytes filter paper (DLFP) as an alternative source of enzyme to assay heparan sulfamidase and galactocerebrosidase activities, which could not be measured in DBFP samples using fluorometric methods. We present a new fluorometric methods on DLFP samples, for evaluation of α-glucosidase (GAA), β-glucosidase (GBA), and N-acetylgalactosamine-6-sulfatase (GALNS) activities, key enzyme assays for the identification of patients with Pompe disease (PD), Gaucher disease (GD), and Morquio A disease (MD), respectively. Results We show a clear discrimination between confirmed PD, GD, and MD patients and healthy controls. Conclusions We conclude that the assays of GAA, GBA, and GALNS on DLFP are reliable and useful methods for the identification of PD, GD, and MD diseases, respectively. As sample preparation is feasible in standard biochemical laboratories and transportation is very simple, it could enable patients living in remote areas to be investigated, diagnosed and eventually treated with the specific therapies available for these diseases.

Background Niemann–Pick type C (NPC) is a treatable genetic disorder, mainly characterized by neurological dysfunction and liver damage. Its diagnosis is based on an invasive test which requires a skin biopsy to demonstrate the cholesterol accumulation in culture fibroblasts of affected patients. In the last years, new biomarkers have been investigated aiming to facilitate the diagnosis and screening of NPC; two of these possible candidates are the oxysterol cholestane-3β,5α,6β-triol (triol), a product of non-enzymatic oxidation of cholesterol, and the enzyme chitotriosidase (CT), a fully active chitinase (EC-3.2.1.14) synthesized by activated macrophages. Methods In this work, we investigated the potential use of the combined analysis of triol levels and CT activity for diagnosis, screening and monitoring of NPC in Brazilian patients, correlating with the results of Filipin staining and genetic analysis. We studied 122 untreated individuals with clinical suspicion of NPC who were separated in two groups according their concentrations of triol (higher or lower than the cutoff value of 100 ng/mL). We also analyzed blood samples from 5 patients with previous diagnosis of NPC who were under treatment with miglustat. Results The results of this work demonstrated that patients with higher concentrations of triol (group A) also presented a high activity of CT and most of them had also a positive Filipin test. Two patients of this group presented an inconclusive Filipin test, being one eventually diagnosed as NPC by molecular investigation and the other eventually diagnosed as Niemann–Pick type A or B (NPA/B) by the low acid sphingomyelinase activity presented. Three patients with high triol concentrations who had a negative result in the Filipin test presented low activities of acid sphingomyelinase, being diagnosed as NPA/B. On the other hand, triol concentrations were normal in NPC patients treated with miglustat, although CT activity in these individuals remained abnormal. In the patients with triol lower than 100 ng/mL (group B), most presented a normal activity of CT. No patient of this group had a positive Filipin test and the few patients with inconclusive Filipin test did not present pathogenic mutations in the NPC1 or NPC2 genes. Conclusions In conclusion, our data demonstrated that the combined analysis of triol and CT is quite sensitive and specific for the identification of NPC patients. Although the number of analysis in NPC patients treated with miglustat was small, the data indicate that the measurement of triol could also be potentially useful for treatment monitoring.

The initial symptoms of Fabry's disease (FD) may seem harmless and may delay its diagnosis. A survey and screening for FD were performed on men with biopsy-proven angiokeratoma and some of their relatives (n = 29). Three patients were identified. Dermatologists should be aware of this prominent early feature and investigate unexplained cutaneous vascular lesions to detect FD.

To study the incidence of galactosaemia in the state of Sao Paulo and the benefit/cost (B/C) ratio of the introduction of neonatal screening for galactosaemia, comparing it with a selective approach. An enzymatic-colorimetric assay was used for the screening of total galactose (TG) in a sample of 10% of the births in Sao Paulo in one year and positive cases were confirmed by the activity of galactose-1-phosphate uridyltransferase (GALT). Detected and referred cases were genotyped using enzyme restriction studies for Q188R, N314D and S135L mutations of the GALT gene. The economic analysis was determined by calculating the B/C ratio and by analysis of sensitivity as a function of the incidence of the disease detected and the variation of the interest rate in the economy. 59 953 newborns were screened for TG, with 3 cases of galactosaemia being identified (0.26% false positives), corresponding to a frequency of 1:19 984 liveborns (95% confidence interval: 1:7494 to 1:59 953). One classical case and one Duarte 2 variant referred to as a selective approach were confirmed. With an incidence of 1:19 984, the B/C ratio was 1.04 for the 11.75% interest rate in effect in Brazil, with values already decapitalized. With a maximum possible incidence of 1:7494, the B/C ratio was 2.79. There is an economic advantage in introducing neonatal screening for galactosaemia in the national neonatal screening programme. This advantage could increase with a reduction of the current interest rates in the economy.

BACKGROUND AND PURPOSE: There are no reliable markers to predict neurologic outcome of patients with mucopolysaccharidosis (MPS) II. We hypothesized that brain MR imaging and MR spectroscopy are useful in depicting features related to cognitive impairment (CI) in MPS II. MATERIALS AND METHODS: Nineteen male patients with MPS II were included in this study. They were evaluated through intelligence/developmental tests to be classified in 2 groups: patients with CI (group A) or patients without CI (group B). Brain MR imaging evaluated white matter (WM) lesions, hydrocephalus, and brain atrophy. Voxels from MR spectroscopy (point-resolved spectroscopy TE 30 ms) were positioned in the WM of the deep right frontal lobe and at the gray matter (GM) in the posterior occipital cortex across the midline. Comparison of MR imaging and MR spectroscopy findings between these 2 groups and a control group was performed. RESULTS: The mean age of the patients was 9.6 years (group A, 7.08 years old, 12 patients; group B, 14 years old, 7 patients; P = .076). Brain atrophy and hydrocephalus were more frequently found in group A patients ( P = .006 and P = .029, respectively); these patients also presented more severe WM lesions than patients from group B ( P = .022). Patients from group A also had a higher myo-inositol (mIns)/creatine (Cr) ratio in the GM ( P = .046) and in the WM ( P = .032). The choline/Cr and N- acetylaspartate/Cr ratios were similar in both groups. CONCLUSIONS: Our study showed that severe WM lesions, brain atrophy, hydrocephalus, and elevated mIns/Cr were more common in patients with MPS II and with CI.

Aim To report the effect of enzyme replacement therapy (ERT) in sympathetic skin responses (SSR) of patients with Fabry disease. Patients and methods Seven male patients were included in an open-label protocol using agalsidase-alfa, continued at regular intervals. Five patients completed 24 months of ERT and two of them completed 18 months. Two main measurements were performed at baseline, as well as 1 and 2 years after ERT: (1) a standard neurological examination (NE), with a detailed evaluation of the sensory perception of light touch, pinprick, cold, hot, and vibratory stimuli; (2) the SSR amplitudes. Results Although there were no significant differences between NE in this time period, all patients reported general improvement in their subjective reports of acroparaesthesia and sweating. Before starting ERT, the SSR amplitudes were either too small (3/7 patients) or absent (4/7 patients): the average (range) amplitude of 122 μV (0 through 492) was statistically smaller than that found in a control group, i.e. 1453.6 μV (619.7–2754) (p

Mucopolysaccharidosis I (MPS I) is a lysosomal disorder characterized by a deficiency of the enzyme alpha-L: -iduronidase (IDUA), which is responsible for the degradation of glycosaminoglycans (GAGs). This deficiency leads to the accumulation of dermatan and heparan sulphate in lysosomes. Presently available treatments include bone marrow transplantation and enzyme replacement therapies, both of which are limited in their effects. In this work, knockout (KO) MPS I mice were treated with a nonviral vector containing the human IDUA cDNA. KO mice were transfected by hydrodynamic injection of pRIDUA in the caudal vein (i.v., n = 3) or by intraperitoneal injection of pRIDUA/Superfect complexes (i.p., n = 3). GAG concentration and IDUA activity were analysed in the kidneys, spleen, lungs, brain and liver. The expression of IDUA in the organs of i.v.- and i.p.-treated mice was also analysed by real-time reverse-transcription (RT) PCR and compared by relative quantification. The concentration of GAGs in the organs differed between KO and wild-type mice. In the spleen and liver, GAG levels were lower in i.v.- and i.p.-treated KO mice than in control nontreated animals. Real-time RT-PCR showed that the transgene is expressed in all the analysed organs of i.p.- and i.v.-treated KO mice. Enzyme activity was similarly observed in all the organs analysed. Our data suggest that this kind of transfection may be a useful tool for studies of nonviral protocols for gene therapy of MPS.

Introduction Le migalastat est un chaperon pharmacologique par voie orale qui se fixe sur certaines formes mutantes et instables de l’α GAL A, sensibles au migalastat afin de restaurer leur transfert vers le lysosome et leur activite enzymatique. Patients et methodes Des analyses en sous-groupe ont evalue le benefice du migalastat sur 24 mois, dans une cohorte de patients de sexe masculin, naifs de traitement par enzymotherapie substitutive issus de l’etude de phase III FACETS. Soixante-sept patients avec mutations sensibles ou non au migalastat ont ete randomises ; quatorze hommes sur les 50 patients randomises avec mutations sensibles presentaient une forme classique de la maladie, avec atteinte multiorganique et une activite enzymatique residuelle plasmatique de l’ α-Gal A Resultats Le DFGe CKD-EPI a l’inclusion etait de 87,8 mL/min/1,73 m 2 ( ± 33,6 DS), avec une variation annuelle moyenne a 24 mois de −0,3 (IC 95 % : −2,8, 2,3). L’IMVG a l’inclusion etait de 114 ± 27,3 g/m 2 , avec 7/14 patients presentant une HVG a baseline . L’IMVG a 24 mois etait a −16,7 g/m 2 (IC 95 % : −31,1, −2,4). Le taux plasmatique de lyso-Gb3 etait de 99,8 ± 35,3 nmol/L, avec une variation par rapport a l’inclusion a 12 mois de −36,8 (IC 95 % : −69,9, −3,7). L’echelle GSRS presentait un score a l’inclusion de 2,5 ± 1,66 avec une variation par rapport a l’inclusion a 24 mois de −0,9 (IC 95 % : − 2,1, 0,4). Discussion Le migalastat ayant demontre une efficacite chez tous les types de patients, les hommes atteints de la forme classique, les hommes atteints de la forme non classique et les femmes, ce traitement pourrait apporter un benefice a tous les patients presentant des mutations sensibles. Conclusion Ces resultats demontrent le benefice clinique du migalastat chez les hommes atteints d’une forme classique de la maladie de Fabry associee a des mutations sensibles a la fois sur la fonction renale, l’IMVG, le taux plasmatique de lyso-Gb3 et les symptomes digestifs et sont consistants avec ceux observes dans la population globale de l’etude.

Mucopolysaccharidosis type I is a rare autosomal recessive disorder caused by deficiency of α-l-iduronidase (IDUA) which leads to a wide spectrum of clinical severity. Here, we describe the case of four male patients who present the previously undescribed p.L18P mutation. Patient 1 (p.L18P/p.L18P) presents, despite multiple joint contractures, an attenuated phenotype. Patient 2 (p.L18P/p.W402X) was diagnosed at 4 years of age with bone dysplasia, coarse facies, limited mobility, claw hands and underwent bilateral carpal tunnel surgery at 6 years of age. Patients 3 and 4 (both p.L18P/p.L18P) are brothers. Patient 3 was diagnosed at 4 years of age, when presented claw hands, lower limb and shoulder pain, restricted articular movement and bilateral carpal tunnel syndrome. Patient 4 was diagnosed at 17 months of age when presented lower limb pain at night, respiratory allergy and repeated upper airways infections. Bioinformatics analysis indicates that p.L18P mutation reduces the signal peptide to 25 amino acids and alters its secondary structure. In conclusion, we report a new IDUA variant that alters the structure of the signal peptide, which likely impairs transport to lysosomes. Moreover, it leads to a distinct attenuated phenotype with mainly bone and cartilage symptoms, without visceromegalies, heart disease, or cognitive impairment.

In this study, 103 unrelated South-American patients with mucopolysaccharidosis type II (MPS II) were investigated aiming at the identification of iduronate-2-sulfatase (IDS) disease causing mutations and the possibility of some insights on the genotype-phenotype correlation The strategy used for genotyping involved the identification of the previously reported inversion/disruption of the IDS gene by PCR and screening for other mutations by PCR/SSCP. The exons with altered mobility on SSCP were sequenced, as well as all the exons of patients with no SSCP alteration. By using this strategy, we were able to find the pathogenic mutation in all patients. Alterations such as inversion/disruption and partial/total deletions of the IDS gene were found in 20/103 (19%) patients. Small insertions/deletions/indels (

Lysosomal acid lipase (LAL) deficiency produces two well defined inborn disorders, Wolman disease (WD) and cholesteryl ester storage disease (CESD). WD is a severe, early-onset condition involving massive storage of triglycerides and cholesteryl esters in the liver, with death usually occurring before one year of life. CESD is a more attenuated, later-onset disease that leads to a progressive and variable liver dysfunction. Diagnosis of LAL deficiency is mainly based on the enzyme assay of LAL activity in fibroblasts. Recently, a selective acid lipase inhibitor was used for the determination of enzyme activity in dried-blood filter paper (DBFP) samples. To extend and to validate these studies, we tested LAL activity with selective inhibition on DBFP samples, leukocytes and fibroblasts. Our results showed a clear discrimination between patients with LAL deficiency and healthy controls when using DBFP, leukocytes or fibroblasts (p

Classical galactosaemia, deficiency of galactose-1-phosphate uridyltransferase (GALT), is characterized by acute symptoms of hepatomegaly, jaundice, sepsis, cataracts and growth retardation. Treatment with dietary galactose restriction corrects these complications immediately; however, most of these children develop long-term complications of verbal dyspraxia, mental retardation and ovarian failure. Our previous molecular study showed that the most common mutation of the GALT gene is a missense mutation of Q188R (replacement of glutamine-188 by arginine) in approximately 60-65% of the German galactosaemic population. The coding region of GALT was amplified by the polymerase chain reaction from genomic DNA of classical galactosaemic individuals, who are negative or heterozygous for Q188R, and was further characterized by direct sequencing. Three new disease-causing mutations, two missense and a stop codon mutation, were identified in three patients from two families with mild galactosaemic variants: firstly R67C, replacement of arginine-67 by cysteine and W316X, the stop codon at tryptophan-316 in one male; secondly A330V, replacement of alanine-330 by valine in two female siblings. In the first family the patient was also heterozygous for the polymorphism N314D and in the second family both girls were compound heterozygotes for Q188R and A330V. All three galactosaemic individuals have a considerable amount of the residual GALT activity in RBC and the galactose-1-phosphate (GALP) level decreased much faster on treatment than that of other galactosaemic patients with missense mutations such as Q188R. The clinical and biochemical data of these patients were much more favourable in comparison with those of two female galactosaemic individuals, one homozygous for L195P and the other compound heterozygous for Q188R and L195P. These three missense mutations (R67C, L195P and A330V) also occur in highly conserved regions. These observations suggest that the phenotypic variation in galactosaemic individuals may be due to different molecular aetiologies.

Although lysosomal storage disorders (LSDs) are considered individually rare, as a group they present a non-negligible frequency. Few studies have been made of populational occurrence of LSDs; they have been conducted predominantly on Caucasian populations. We studied the occurrence of LSDs in Cuba. Data from individuals who had been referred to the Institute of Neurology and Neurosurgery in Havana from hospitals all over the country between January 1990 and December 2005 were analyzed. This institute was the only laboratory to provide enzyme-based diagnostic testing for 19 LSDs in Cuba during this period. Occurrence rates were calculated by dividing the number of postnatal diagnoses by the number of births during the study period. The combined occurrence of LSDs in Cuba was 5.6 per 100,000, lower than that reported in other studies conducted on Caucasian populations. The most frequent individual LSDs were: mucopolysaccharidosis type I (1.01 per 100,000) and, surprisingly, alpha-mannosidosis (0.72 per 100,000) and fucosidosis (0.62 per 100,000). These findings may be related to specific genetic characteristics and admixture of the Cuban population. This is the first comprehensive study of the occurrence of LSDs in Cuba. We conclude that the epidemiology of these diseases can vary regionally, and we stress the need for similar surveys in other Latin American countries.

Hunter syndrome, or Mucopolysaccharidosis type II (MPS II), is a rare X-linked recessive disorder caused by a deficiency of the lysosomal enzyme iduronate-2-sulfatase (IDS). The phenotypic spectrum varies from severe to attenuated clinical forms. We report a large Brazilian family with 16 affected individuals exhibiting a very attenuated form of MPS II. Fourteen female carriers were also identified. Twelve affected male patients, whose ages ranged from 1 to 35 years, were examined. Molecular analysis showed a novel missense mutation (p.A77D) in the IDS gene, confirming the diagnosis. Nine of the family members presented some degree of heart damage, though only the proband became symptomatic and required heart transplantation. One 19-year-old adult and 1-year-old twin boys each had a normal echocardiogram. Short stature was found in two adults while macrocephaly was found in one; the remaining adults had anthropometric measures within normal range. All affected adults had normal cognitive development and were able to perform normal daily activities, except one who had mild learning disability. Two patients died due to natural causes beyond 70 years of age. The female carriers did not present any signs of disease. In this large family with a mild form of MPS II and variable degree of clinical manifestations, it is noteworthy that several affected individuals have remained asymptomatic even at advanced age and even without enzyme replacement therapy.

The initial symptoms of Fabry's disease (FD) may seem harmless and may delay its diagnosis. A survey and screening for FD were performed on men with biopsy-proven angiokeratoma and some of their relatives (n = 29). Three patients were identified. Dermatologists should be aware of this prominent early feature and investigate unexplained cutaneous vascular lesions to detect FD.

This study was designed to evaluate the effect of mycoplasma contamination on acid hydrolase activity and the action of the mycoplasma removal agent (MRA), in cultures of human fibroblasts from individuals with lysosomal diseases. For this purpose, we measured the activity of the b-galactosidase, arylsulphatase B (ASB), hexosaminidase A and a-glucosidase enzymes. The activity of the above mentioned enzymes in fibroblasts contaminated by mycoplasma was measured before and after the addition of the MRA. The results were then compared to the enzymatic activity in contamination-free cultures. Only the ASB enzyme showed significant alteration in activity both in the presence of mycoplasma and MRA. The remaining enzymes did not suffer significant interference by the presence of the two agents. Of the four enzymes tested, three did not suffer significant alterations by the presence of the mycoplasma nor from the MRA. However, the activity measured in the ASB enzyme increased significantly in the presence of mycoplasma and MRA and could lead to a doubtful diagnosis. Therefore, we suggest that contamination should be prevented by using aseptic techniques as well as the MRA in those fibroblast cultures that cannot be discarded.